Ball-mill



F. E. CANDA.

BALL MILL.

APPLICATION FILED MAY 13, 1916.

F. E. CANDA.

BALL MILL.

APPLICATION FILED MAY I3, 1916.

Patented Apr. 20, 1920.

UITED sTATEs PATENT onnron.

FERDINAND E. CANDA, OF NEW YORK, N. Y.

BALL-Mini..

Specication of Letters Patent.

Patented Apr. 2o, 1920.

Applicationled May 13, 1916. Serial No. 97,224.

tures as hereinafter described and particularly pointed out in theappended claims,

As such mills have been generally constructed heretofore, the shellitself has been a member separate and distinct from the wearing Vface ofthe mill, such wearing face consisting of a hollow member insert edwithin and held in place in the shell proper; and this shell proper hascommonly been formed in two members7 each cylindrical and each havingformed inte rally with it one of 'the heads of the mi thetwo members ofthe shell parting at the center of the mill in a plane of rotation ofthe shell. To this construction there are various objections. At thedischarge head of the mill there are usually. certain radial membersforming a support for the grating or screen of the mill, and whichshould be machined to afford an even support for the grating; but thedepth of the shell is such that it is impracticable to machine suchradial members by ordinary tools,.for which reason they are usually leftunmachined, and therefore uneven, and therefore the grating is notevenly supported, for which reason much wear of the grate members mayoccur and breakage of the grate members may also occur. Also there ismuch leakage. through theb'olt holes through which pass the boltsconnecting the wearing member to the shell. A further objection ofv theold construction of mill referred to is that the said wearing face ofthe mill must be a castmember,

whereas if thiswearing face may be formed of rolled members of hardsteel, such for example as chrome steel, they will be much more durable.

"By my present invention l avoid occasion for use of a wearing face ormember separate and distinct from the shell itself; the shell itself,the inner surface of which is also the wearing face, is formed ofsegments which may be fastened together to complete the shell and alsothe wearing face, and these segments are of such form that they may berolled; the heads of the mill are separate from the shell segments, and

vtherefore may be machined readily; access to the interior' of the millmay be gained readily by removal of one of the heads of the mill; theseveral segments constituting the shell of the mill, and also itswearing face7 are so fastened together that a rigid structure isproduced, and that passage of dust or mud through the joints between thesegments is obviated; also Ythe millas a whole is lighter, for equalservice and capacity, than the former mills above referred to.

Other features of my invention will be pointed out hereafter.

The objects of my invention are, to improve the construction of ballmills, particularly mills of the type referred to; to

. make the Wearing face of the mill of such construction that its partsmay be produced by rolling'or pressing, and therefore may be formed ofsteel or other very hard material which nevertheless possesses the grainand fiber characteristic of metal which has been worked, asdistinguished from cast metal; to construct the said wear-V ing memberin such manner that it may also ferm the shell of a mill, dispensingwith any separate shell; to so arrange and construct the parts of thiswearing member that such parts are' readily assembled, and whenassembled form a rigid structure throughrthe joints of which dust andmud will not escape; to so construct the mill that the heads thereof arereadily separable from the shell proper, which heads may therefore bemachined readily; to attach theseA heads to the shell proper in a`secure yet simple manner; and to make the mill of lighter weight, forequal size and service, than former mills of similar type.

l will now proceed to describe my invention with reference to theaccompanying drawings and willthen point out the novel features inclaims.

in the drawings: r

vFigure l shows in art afragmentary end view, looking from t echargingend of the mill, and in parta fragmentary transverse section ofthe mill, showing segments of the grate.

Fig. 2 shows a fragmentary transverse section of a mill similar to thatshown in Fig. 1, but embodying anI alternative construction o f shell,two grating sections only being shown, and a portion of the dischargehead of the mill being shown in elevation.

Fig. 3 shows a fragmentary axial' section of the discharge end portionof a mill such as shown in Fig. 1, the section being taken on thesection line 3-3 of Fig. 1.

Fig. 4 shows a fragmentary axial section of the discharge portionV of amill such as shown in the previous figures, the section eing taken onthe section line 4 4 of Fig. 5 shows in part an axial section of thecharging end of 'a mill such as shown in Fig. 1, and in part a sideelevation of the discharge end of the mill, one of the rows of coactinglugs on the exterior of the mill being sectioned in a plane parallel tothe axis of the shell, to show the inserted Fig. 6 is a fragmentarysection on the line 4-f4 of Fig. 2, but on a larger scale than Fig. 4,and shows particularly the means for pressing thegrate bars together.

Fig.y 7 is-a detail side view of one of the wedge-headed bolts shown inFigs. 4 and 6, and in other figures of' the drawings.

Fig. 8 is a fragmentar detail sectional view, the section being ta renon the line 8 of Fig. 1, and shows improved means for clamping the gratebars at their ends.

Referring first to Figs. 1, 3, 4 and 5: 1

designates the shell of the mill, 2 the receiv-I` ing head of the mill,3 the discharge head thereof, 4 the hollow trunnion of the receiving endof the mill and 5 the hollow trunnion of the discharge end of the mill.It will be understood that the structure 1-2-3, is adapted for mountingin suitable bearings for rotation, the hollow trunnions 4 and 5constituting the journals; also that the structure 1 2-3 will beprovided with means of customary nature for rotating it, which means arenot shown in the drawings. The shell 1 is formed of segments 1a providedat their meeting faces with lugs 6 having registering apertures for thepassage of suitable fastening bolts 7. These segments 1a are provided,on their interior faces, with suitable rises 8, forming the usual ribswhich cause the crusher balls, (not shown in the drawings, since theyform no portion of the present invention) to lift and then fall on rockin the spaces between these rises. The segments 1u therefore form boththe shell of the mill and the wearing member. That these segments 1u maybe fitted together accurately and rigidly, and that passage of dust ormud through the joints of the segments may be prevented, the meetingfaces -`of the various segments 1a are provided with key grooves 9 andsuitable keys 10 are fitted within these grooves. The result is theformation of an'exceedover the surfaces of the radial ribs 11 and 12formed integrally with head 3 which re-y ceive' and support the gratingsegments 13.

. These grating segments maybe of any usual construction, but preferablyare of the construction of my application Serial No. 95,312, filed May4, 1916. These grating segments are held in place by wedge bars 14 (Fig.8) and bolts 15. The heads 2 and 3 are held to the shell -1 by ,means ofbars 16 engaging a number of bolts 7 which hold the shell segmentstogether, and passing through suitable apertures in said heads andprovided, outside of such heads, with suitable clamping nuts. Thisprovides a very rigid connection of the heads to the shell.

Each segment 1a is seated at its ends in grooves 17 in the heads of themill; whereby a very tight joint is formed between the shell proper andthe heads.

In the construction shown in Fig. 1, each segment 11 of the shell andwearing member isformed with two halves of rises 8; each complete risebeing formed ofhalf rises of two adjacent segments. In the constructionshown in Fig. 2, each segment of the shell, which segments are heredesignated by'numerals 8b, is provided with a complete rise 8 located atabout the center of the segment. The two constructions are substantialequivalents one of another, and either may be employed as preferred.

Any suitable means may be employed for pressing the several bars of thegrate sections 13 toward the center and so for holding those grate barsrigidly. I have illustrated, inthe drawings, but particularly'in Fig. 6,a preferred construction wherein the discharge head of the mill hasfitted into it segments 18 each having an obliquefaced rib 19 fittinginto a corresponding groove of the head 3. Wedge-headed bolts 2() suchas shown in Fig. 7, fit into slots of the member 18 and pass throughapertures of the head 3, and are provided outside of such head withsuitable nuts, whereby they may be drawn up. Owing to the wedgeshape ofthe heads of these bolts 20, and the corresponding wedge-shape of thebottoms of the slots in segments 18 in which such wedge-shaped headsfit, drawing up oblique steps 22; and between the ends otl the gratebars 21 ot' adjacent grate segments 13 correspondingly stepped clampingbars 1l are placed. It will be clear that by drawing down these bars 14by means of the bolts 15 the grate bars 21 are held firmly at theirends.

What I claim is:

1. A ball mill such as described comprising a cylindrical wearing memberformed ot' a plurality of segments. bolts connecting said segments,heads for said cylindrical member, and bars directly engaging the saidbolts and secured to said heads.

2. A ball mill such as described comprising a cylindrical combinedwearing member and shell formed ot a plurality of radial segmentssecured one to another, heads secured to Asaid cylindrical member. oneof said heads having a discharge opening near lits center and havingintegral ribs on its inner face, and a grating seated directly on saidribs and secured to such head, the construction being such that becausethe said heads are separate from the said combined wearing member andshell the faces of said i ibs adjacent said grating may be machinedreadily.

3. A ball mill such as described comprising a shell with at least oneseparable head, said head having a grating-support, and a grating onsuch support comprising a series of segments each formed of a pluralityot grate bars. and means for pressing such grate barsinward and togethercomprising wedge-headed bolts extending to'the exterior of the head andmeans-for drawing such bolts outward.

Ll. A ball mill such as described comprising a head having agrate-support provided -With a groove and a grating on such supportcomprising a series of radial segments each formed oi a plurality ofgrate bars, ring segments located across the ends of such g ate-segmentsand each seated in said groove of such grate support, and Wedgeheadedbolts seated in such ring segments and pressing against the outer baror" the correspondnig grate segment and adapted to press the grate barsof that grate segment together.

5. A ball mill such as described comprising a head having agrate-support and a grating on such support comprising a series ofradial segments each Jformed of a plurality of grate bars, ring segmentslocated across the ends ot' such grate segments and each seated in agroove of such grate support and provided With an oblique-faced ribtitting into a correspondingly oblique-faced groove of such support, andwedges working against such ring segments and also against the outer barof the corresponding grate segments and adapted to press the grate barsof that grate segment together.

6. A ball mill such as described comprising a head having agrate-support having ribs, and a grating on such support comprising aplurality of radial segments each comprising a plurality of grate barsthe ends ot' which rest upon such ribs and are provided with obliquesteps, correspondingly obliquely-stepped clamping bars fitting betweenthe ends of the frate bars of adjacent grate segments and having theiroblique steps resting-upon the oblique steps of the corresponding gratebars, and means for holding such clamping bars down.

In testimony whereof I havesigned 'this specification in the presence oftvvo subscribing Witnesses.

FERDINAND E. CANDA. lVitnesses H. M. MARBLE, PAUL H. FRANKE.

